Rotor of an electric machine having an exciting current supply lead

Abstract

In large electric machines, the electrical connection between the exciter supply lead (7, 8), which extends axially in the center of the rotor, and the exciter winding conductors (4) in the winding overhang (3) of the rotor is highly stressed electrically and mechanically. If use is made of an elastic exciter terminal stud (13) made from steel, and the connecting conductors (17, 18) are supported between the exciter terminal stud (13) and the conductors (4) of the rotor winding overhang on the rotor cap, preferably on its cap plate (6), excessive stresses occur neither on the shaft (2) nor on the connecting conductors (17, 18). It is preferable in this arrangement to make use of a terminal stud (13) that is slotted in the longitudinal direction of the stud and has at least three slots. Such a stud is elastic transversely to its longitudinal direction and can be purposively cooled.

What is claimed as new and desired to be secured by letters patent of the United States is: 
     
       1. A rotor of an electric machine, in particular a turbo-generator, having an exciting current supply lead for connecting an exciter lead, which extends axially in a center of the rotor, to exciter winding conductors in a winding overhand of the rotor, which rotor has a rotor cap for supporting the winding overhang of the exciter winding conductors, having an exciter terminal stud made from steel, which is arranged in a radial shaft bore-hole and is connected at its inner end to the said exciter lead and is connected electrically and mechanically at its outer end outside a rotor shaft via connecting conductors to the exciter winding conductors of the rotor winding overhang, and having means for supporting the said connecting conductors, wherein the said connecting conductors are supported on the rotor cap in an electrically insulated fashion, and the exciter terminal stud is elastic transverse to a longitudinal direction of the stud. 
     
     
       2. The rotor as claimed in claim 1, wherein the connecting conductor is constructed in two parts and comprises a lug on a winding-terminal side, and a contact part on a stud side, the two parts being connected detachably to one another, and a connecting point of the two parts being located between a support point on a rotor cap and a rotor winding termination on the rotor winding overhang. 
     
     
       3. The rotor as claimed in claim 2, wherein the part, facing the exciter terminal stud, of the contact part is flattened and provided at its end with an eye for fixing to the exciter terminal stud, and the other end is constructed cylindrically and has a connecting eye. 
     
     
       4. The rotor as claimed in claim 3, wherein at the cylindrical end the contact part is fixed detachably to the cap plate in an insulated fashion by means of a retaining bow. 
     
     
       5. The rotor as claimed in claim 4, wherein for the purpose of electrically insulating the cylindrical end with respect to the cap plate the former is surrounded by an insulating sleeve. 
     
     
       6. Rotor as claimed in one of claims 1 to 5, wherein a shank of the exciter terminal stud is slotted in the longitudinal direction of the stud, at least three slots being provided which extend radially up top stud axis. 
     
     
       7. Rotor as claimed in claim 6, wherein the stud is provided with a through bore-hole penetrating the entire stud. 
     
     
       8. Rotor as claimed in claim 6, wherein the shank is constructed conically with a thicker end being at an internal stud end. 
     
     
       9. Rotor as claimed in claim 6, wherein there is pushed over the stud a thin-walled hollow cylinder which is supported by an inwardly projecting projection on a collar on the stud at a level of a transition from a thread to the shank. 
     
     
       10. Rotor as claimed in claim 9, wherein the slots in the stud penetrate said collar. 
     
     
       11. Rotor as claimed in one of claims 1 to 5, wherein there is arranged on a rotor cap a cover cylinder which extends axially up to and over the exciter terminal stud, and there is provided at a free end of the cover cylinder a metal block which serves as a constant element and which has a contact surface which is spaced from a radially outer end of the exciter terminal stud by a gap. 
     
     
       12. The rotor of claim 1, wherein said rotor cap includes a cap ring and a cap plate, and wherein said connecting conductors are supported by said cap plate. 
     
     
       13. The rotor of claim 12, further including a cover cylinder connected to said cap plate and extending over said exciter terminal stud. 
     
     
       14. The rotor of claim 1, wherein said connecting conductors extend in a direction transverse to the longitudinal direction of said exciter terminal stud.